Top diplomats from Iran, Russia and Turkey met Sunday morning in Antalya to discuss the civil war in Syria ahead of a three-way summit in the Russian city of Sochi on Wednesday.

Turkish Foreign Minister Mevlut Cavusoglu met with his Russian counterpart Sergei Lavrov and Mohammad Javad Zarif of Iran and in the southern Turkish city for the closed-door meeting, an official said.

He declined to provide further details on the meeting, which comes as violence is diminishing in Syria's six-year war although a political solution still seems out of reach.

Moscow, Tehran and Ankara are sponsoring the so-called Astana peace talks, named for the Kazakh capital where they are regularly held, which calls for the creation of "de-escalation" zones in key areas of Syria.

Although Turkey has supported rebels looking to overthrow President Bashar al-Assad's government, it has muted its critiques of the Syrian regime, which is backed by Russia and Iran.

Russian President Vladimir Putin will host Turkey's Recep Tayyip Erdogan and Iran's Hassan Rouhani for the Sochi summit, where talks on reducing violence and ensuring humanitarian aid are on the agenda.

According to the Anadolu news agency, Putin and Erdogan have already met five times this year and spoken by telephone 13 times.

Erdogan last met Putin for talks in Sochi on November 13, agreeing on the need to boost elements for a lasting settlement.